BUCKLING AND POSTBUCKLING BEHAVIOR OF A PIPE SUBJECTED TO INTERNAL-PRESSURE

It is well known that a thin elastic shell under external pressure may undergo buckling and collapse. Less well known is that a hollow beam under internal pressure may buckle as an Euler column. This is the sub ject of the present study. The buckled deflection and natural frequenc y about the buckled configuration. of a vertical pipe with clamped (y- axis) and hinged (z-axis) boundary conditions at the lower support loc ation, considering the influence of internal pressure and initial (man ufactured) curvature, has been studied analytically and experimentally , The buckling and postbuckling behavior of the pipe beam with an init ial static deflection depends upon the nonlinear coupling due to defle ction in the two directions including the anisotropic boundary conditi on at the one support location. The coupling effects increase as the i nternal pressure and the initial static deflection increase. When the initial static deflection is zero, the coupling effect disappears. The theoretical results agree reasonably well with the experiments.